Apparatus for weight classification



Dec. 1, 1953 N. G. MALoNEY APPARATUS FOR WEIGHT CLASSIFICATION 4 Sheets-Sheet l Filed Jan. 24, 1951 LMC uw a. .lL/4, E /m/ NN TT ORNE Y.

Dec. l, 1953 N. G. MALoNz-:Y

APPARATUS FOR WEIGHT CLASSIFICATION 4 Sheets-Sheet 2 Filed Jan. 24, 1951 ATTORNEY.

Dec. l, 1953 N. G. MALoNr-:Y

APPARATUS FOR WEIGHT CLASSIFICATION 4 Sheets-Sheet 5v Filed Jan. 24, 1951 5.1611 ywfn elm n mm afl-.

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Dec. 1, 1953 N. G. MALONEY APPARATUS FOR WEIGHT CLASSIFICATION Filed Jan. 24, 1951 4 sheets-sheet 4 `\Z7 INI/ENTOR.

Norv/'n G.Ma/oney ATTORNEY Patented Dec. 1, 1953 UNITED STAT'v LWN OFFICE APPARATUS FOR. WEGHT CLASSIFICATON l Application January 24, 195i, Serial No. 267,636

10 Claims. 1

This invention relates to an improved apparatus for weight classification, and particularly to apparatus for the weight classicaticn ci succession of articles moving at relatively high speeds.

Technological development in the eld of packaging and filling materials into containers has provided industry with high speed equip ment of very high capacity output. The use of such equipment introduces a serious problem, in that presently available inspection equipment for the determination of underweight or overweight conditions is not adapted to operation at speeds matching those obtained by the packaging and iilling machinery. Weighing comparison of packaged products against a standard mass as now practised involves balancing one mass against another by the use of a scale beam or its equivalent and, after the system has reached equilibrium,

determining the direction and sometimes the degree of deviation existing. Such comparison requires movement of an indicating element to a position at or near rest, which may involve a succession oi" cyclical swings past an equilibrium line, or at least an approach to equilibrium, followed by damping, to permit near attainment of the equilibrium state before an accurate comn parison of the standard and the product is possible. With such systems an appreciable interval of time is required to make each weight comi parison and the processing rate is therefore relatively low.

A special system of weight classification applicable to cylindrically shaped objects which are capable of rolling movement has been develcped recently, but use is limited to articles of this particular shape and any deviations in form, such as indentations or upraised portions along the peripheries, introduce errors which, under high speed conditions especially, are of relatively large magnitude.

A principal object of this invention is to pro vide a rapid and accurate method and apparatus for the weight classication of a succession of articles moving at relatively high speeds. Et further intended to provide an apparatus for weight classiiication having a long operating life, automatic functioning, and a construction requiring little maintenance.

Other obiects of this invention will become apparent from this description and the following drawings in which:

Figs. l and la are plan views in continuation of one embodiment of apparatus constructed according to this invention,

Figs. 2 and 2a are side elevation views in continuation of the apparatus shown in Figs. l and la,

Fig. 3 is a top plan view of several packagecarrying pallets showing their relation to the conveyor chains,

Fig. 4 is a side elevation view of a Weighing platform with the conveyor bed shown in partial section,

Fig. 5 is a sectional View taken along line 5-5 of Fig. 4,

Fig. 6 is a sectional view taken along line 6 6 of Fig. 4,

Fig. '7 is a sectional view taken along line '1 -l of Fig. l1,

Fig. 8 is a sectional View taken along line 3 8 of Fig. 11,

Fig. 9 is a sectional view taken along line -Q of Fig. 10,

Fig. l0 is a sectional view taken along line iii-lll of Fig. 2,

Fig. 11 is a View looking along line il-ll of Fig. 2,

Fig. l2 is a side elevation view showing a preferred construction and arrangement of drag links connecting successive package-carrying pallets.

Generally, the objects of this invention are attained by determining the relationship of a product mass to a standard mass by the rate of acfceleraticn of a system balanced with respect to the standard mass, the determination being made while the product mass is being translated across the system at substantially uniform velocity, and effecting the comparison of the product mass with the standard mass within a very limited displacement range from the systems position of rest. As will become apparent from the following detailed description, the comparison of masses necessary to the Weight classification of a succession of articles or packages according to this invention may be accomplished with a very high degree of accuracy during a very short in terval of time, thus making it possible to process the articles or packages at output rates at least equal to the output rates of modern highspeed supplying. equipment. In a typical case,

a package filling machine might continuously deliver as many as 35i-' or more packages per minute of a nominal weight of three pounds each. The weight classication of such a high product iiow to safeguard against under-filling or cver-lling within the brief time interval of 1/5 second per unit constitutes a difiicult problem. Necessarily, continuous operation at speeds of the order cited require the use of fully automatic such as to require a minimum of maintenance in order to conserve production time.

Referring to Figures i, lo, 2 2a, one einbodiment of apparatus according to this invention may comprise an endless conveyor system adapted to translate a succession of articles conu tinuously across a weighing platform, which is one element of a balanced system for. the oonparison of the masses of. the individual arL yles with a standard mass. Additional apparatus is provided for cyclically locking and unlocking the weighing platform in aio-ordination with the movement of articles across it, so that' the s'- s-l tem is restored to base position upon, completion of the weighing of each article in turn. Finally, automatic detection equipment is provided for sensing the degree and direction. of deviation of each article mass from the standard mass and for actuating classification devices adapted to segregate articles which are either under or over a prescribed acceptable weight.

The conveyor system and the weighing tus co-operating therewith may be conveniently mounted upon a common frame lli. The con veyor shown may consist of two endless roller chains, indicated'generally at l E', each chain being supported by suitable sprockets i4 and ifi", jacent of which are keyed or otherwise secured to common shafts I5 and ifz, respectively- Shafts I5 and I5 are Iiournaled in support brackets IG and. I respectively, attached' to frame Il. As shown in Fig. 1, shaft l5 is previded with sprocket I1 fixed thereto, andis driven from motor' i8, which is preferably of the syir chronous type, through drive chain l5. Spree-l1: 2t, keyed to shaft i5, drives the weighing pl forni locking and unlocking mechanism', h after described, through roller chain 2|. u s with sprocket 22 (refer Figs. 9 and lfl); losi ve driving means, such as that provided by roller chains and sprockets, are employed throughout because of the necessity of exactly co-ordinating the movement of the articles to be classiiied with the operation of the weighing' mechanism.

Frame I l is providedwith a smooth, plane tablesurface 23 (Figs. a, 7, 8 and 9) for support of the articles 2t, which are toA be classified oording to weight or,` more desirably, for the support of pallets 25` carrying' the articles, where pallets are employed for the intermediate support ofthe individual articles. A principal advantage inherent in the employment of pallets for the support of articles is that the surfaces which contact table 2'3 and the weighing platw form 2t (Figs. 4.-, 5 and 9) may bemaintainedin essentially the same condition of smoothness, thereby' eliminating variations in the coefoi nts of friction which might adversely affect the operation. Another important advantage is that ver2- tical force components arising from surfacev ir regularities in the articles,l themselves are err tirely eliminated since the'articles are not broute 1 into direct contact with the weighing platform. A further advantage is that pallets may be pro-- vided with cradle supports conforming to' the shapes of the articles being processed, so that articles having a wide variety of shapes may be accommodated by the provision of the proper shape of support' in each case. It will be undern stood, however, that articles capable of taking a stable position while being slid. along, such cylindrical cans' resting on their dat base portions, Inay be processed` satisfactorily without the intermediate support of pallet elements. In the latter case, chains i2 may be provided with cross bars disposed so that they clear table' 23, individual articles Erl being sl'ip'pliedV to the apparatus in such a manner that one is disposed .between each pair of cross bars, the rear cross 'oar of each pair, referred to the direction in which the chain is moved, propelling each article along.

In practice, it has been found that slight de formations inthe exterior. surfaces of the articles contacting the cross bars introducev errors in the weighing, due to the fact that non-compensable Vertical force components are thereby1 applied to the weighing platform. rlhe effect oi' suchdeformationscan be minimized by providing` the cross, bars with freely rotatable ball bearing pusherl elements which transmit the moving force tothe articles. In a typical case wherein cylindrical cans were classified, a pair of ball bearing sets` ('S; A. E. lightiseries #34) were pressed on to the cross` bars a sufficient distance apart to permit locating a can therebetween, while still preventing direct contact of the can with the cross bar. The large diameter external. convex surfaces of the outer race elements of the bearings provided a, relatively sinall area of contact with each can and eliminated much of the interference occasioned by the usual sreail dents and irregularitiesy encountered in can bodi Where the translation of the articles i. effected by pallets which support the articles out direct contact with the weighing platform, the pallets may be provided with rotatable wheels or rollers mounted on the lower sides to minimize the area of contact with. the platform.

A preferred design of pallet suitable for use with this'invention is illustrated in Figs. 3, 7, is. 11 and 12. In this embodiment the pallets coinH prise flat metal plates 25 of sufficient thiclin to support the weights of the articles in proc is without buckling or distortion. Plates ca supporting shoes 3|l securely attached to tno undersides,r which shoes are adapted to slide across the surfaces of table 23 and weighing.' platform. 26. with a substantially constant lcv.' frictionaldrag. Shoes 3l may be fabricated from metal but preferably are constructed from a material. such as polymeric tetrauoroethylene, or thelikawhich possesses a characteristic r'l' peryv surface well suited to this particular ih To minimize wear of' the contacting surfaces relative movement, the apparatus may nicer'- porate'wipers and oil applicators of conventie z. design,A andv therefore not shown or described herein, for cleaning and lubricating shoes El during the lower portion of chain travel. As in dicatedin Figs. 8 and l1 particularly, 'the pallets may each carry ltwo shoes of a length approximately one-half the length of the pallets, the shoes being disposed in the central portions o the pallets, referred to the length dimension, and about one-fourth in from the sides, referred to the width dimension. The inside edges of shoes 3l are preferably undercut so that a niinimurr. area will contact table 23 while still preserving stability of the. pallets as supporting structures. Shoes 3l` are secured to the undersides of plates 25 with an appropriate adhesive, or by clips, screws or other conventional fastenings.

As. shown in Figs. 2 2a, '7, 8, l0, 11 and 12 particularly, pallets 2E are secured to endless roller chains I2, which continuously move the pallets, with article-receiving surfaces upright over the upper portion. of the machine and return the pallets with article-receiving surfaces in.- verted over the lower portion of the machine. Guide rails 2l, integral with frame il, support chains l2 in free rolling contact during the upper path of travel, the length of the individual rollers being sufficient to span the width of rails 21 Without binding. No physical support for chains l2 other than that provided by sprockets ill and lll' is required for the return circuit of chain travel.

A preferred driving connection between pallets and chains l?. is detailed in Figs. 3, ll and l2. ln this arrangement each individual pallet is drawn in the di"ction of chain travel by a drag link connecting it with the preceding pallet, while a second drag linl: 32 connects each pallet with the one nmediately succeeding it. Drag links are formed in the shown so that at no point will they contact the undersides of pallets as chains l2 track around sprockets ifi and M. .i addition, the holes t3, receivincA the ends of the driving cross pins 3d, and the holes receiving the inside ends of the pins tached to pallets (refer 7l, both over-sise, so that the pallets can freely accommodate their travel to changes in direction ccm curring during chain tra@ el and, more important, so that full weights of the pallets th. loads will always transmi ted to shoes during the time the pallets are moved over the length of table Suiiicient lateral clearancis likewise provided at these points to eliminat any lateral binding' between links and adjacent surfaces.

Driving cross pins (refer Fig. 8) are assembled with chains l2 by removing the standard chain roller pins and substituting pins lt will be noted that the horizontal central plane of chain travel coincides with the top of table thus procuring tie application of driving forces in this plane and eliminating any vertical force components which would introduce error into the weighing comparison. The central portions of are offset, so that the pins clear table and are in this position by small di pins or wedge elements (not shown) locking Jrh within associated chain roller elements. assembly further strengthened by washers 3'? pinned to the inside ends of elements links in .tained in place by outside washers pinned to the outer ends. The edges of llets are turned in direction to enclose t lil, for the purpose of protecting table .J ist the entrance of dust or other foreign material which. might change the coefficient of friction existing between the table and shoes (i i, over-sise apertures E@ being provided to facilitate assembly of the several components with the chains.

shown in Fig. '7, pins Sil securing the forcetransmitting ends of links 32, comprise flangeheaded bolts which are ixedly secured to pallets by lo nuts and eli, these pins having no direc coni ction with chains Good stability in force nsrnission is obtained by disposing pins the mid-points of pallets 25. indicated. in l2, and it is also advantageous to locate cross pins et at about rear Quart-ei. points.

A preferred embodiment of weight comparison device according to this invention comprises wcighing platform and its deflecting support structure. including the float and iiexural pivot comi` iation detailed in Figs. 4-6 inclusive, and the locking and unlocking mechanism particularly shown in Figs. 9 and 1G. Table is out to accommodate platform 25, the top surface of which, in locked position, is at the same ration as the top of the table, except for the ht clearance provided for free vertical moveont of with respect to Locking at the position where platform 2li is normally at rest when no load is applied thereto is especially de- 6 sirable in high speed weighing, because the lock serves as a steady rest which prevents the iinposition of interfering forces at the instant of unlock manifested as vibrations.

The entire weighing assembly is supported by a sub-frame All secured to frame Il by bolts d5. Mounted on sub-frame M, by bolts (it, is a bracket 6'.' to which are attached the flexural pivot frames fully shown in Figs. 4 6. The upper frame d3 is preferably an N-truss consisting of three hollow tubular members, the cross member of which is securely soldered or brazed to the two side members. The lower frame 4S may have the form of a il-truss, consisting of a pair of hollow tubular members soldered or braced. together at the ends adjacent the weighing platform. In a typical case these frames were fabricated from 0.1875 O. D. X 0.1520 I. D. cold drawn seamless steel tubing.

The flexural pivot elements comprise short lengths of flat spring steel stock which, for the specific apparatus hereinabove described, consisted of pieces .004 thick, 1%" wide and 11/8 long. Elements 5l! are securely attached to the tubular ends of frames #le and 139 by crimping the tubes iiat around these elements and then completing the bond by sweat soldering. The outer ends of the elements 50 of upper frame l5 are clamped to the upper flanges of bracket il by metal straps 5i secured by bolts 52, and to the underside of platform 2S by metal straps 53 secured by bolts 54. Similarly, the outer ends of the elements 50 of lower frame 'it are clamped to the lower flanges of bracket 41 by metal straps secured by bolts 5S, and to the lower end of hub 5l by nut 58, which is threaded on bolt 59 passed through a hole drilled through the central portion of this particular exural pivot element.

It will be understood that the function of the ilexural pivot elements 50 is to preserve the xed location of weighingplatform 2li with reference to table 23, while at the same time impeding the vertical displacement of platform to a minimum degree. The weight of platform 2S and its supports hereinafter described, as well as the weight of any load applied to 2li, is substantially entirely supported by float E@ immersed in liquid El contained in cup 62.

Referring to Figs. 4 and 5, platform 2t? is supported by four struts 68, which are preferably fabricated from tubular stock of the same size as the members making up frames it and 59, in order to reduce weight. For the same reason the underside of 2@ is recessed to provide a rigid construction while eliminating excess weight. All connections of struts @il with hub 5l and with platform 26 are desirably by silver soldering or brazing.

The lower end of hub 5l is tapped to receive bolt 59 which secures iloat il@ in operative relationship to platform 25. Float te is spherical in shape and is dimensioned so that its limited displacement in the particular liquid iii utilized will be sufficient to permit a comparison of the acceleration of a standard weight, plus the tare weight consisting o 25 and its supports, with the article whose status is to be determined, plus the same tare weight. In a typical installation designed for the weight classication of packages in the three pound range, a steel sphere having a wall thickness of approximately .020 and a diameter of 2112 was entirely satisfactory where mercury was employed as the liquid Si. In this instance surface disturbance, occasioned by the rapid. cyclical operation of the device, was eliminated the entrance ol foreign materials prevented by iioating an iron annular ring: ii on the surface of the liquid, the central hole G4 the"ein being suiliciently large to permit unhani pei-ed movement of bolt Float cup t?? is provif: el v ith. oppositely clis les. 6 and l0) which are on with respect to ot er e... s the Weighing assembly. iii are out i suboranie it to permit lowerini; cup away the platform supporting structure wl rep irs an aintenance require.

" mechanism for the 'e of articles to be classified is shown entire assembly to sub-franie -orizzontal cross member oi plane of the quadri with the lower edge s oi hub to permit free ve I when unlocked. traliy through-50111g Je reciprocatory locking bar ill, which is the cyclical locking andv unlocking hereinafter described in detail.

Locking bar it sliclably inoun ed in a milled way a' the front of yoirf (refer Fig. 9) and is position by oo T plates 313 2li to by bolts The locking bar itself is generally rectangular in shane, ex.- cept that it is provided along the upper with an inclined abutting projection mates wi lar inclined surface con ing the top ol' opening The enti of "I3 acljam cent the re-ciorocatory power .source is provided with powermi fitting; pin llt. both ends ci which also points of attachment for tension f ariel 9). The opposite secured to the encls of g ror Cover plate permit-ing free reciprocation Drive bar .ecurecl to pin in may 'l accomplishes the abutment on the adjacent end of le accomplish the .on of force cal- 3 mechanism.

ift engageflange of constituting one leration detection sysu klement lei in lieariicA posts nce axle lill of mirror of rotation delinea .rrcr will t to turn posts lill; however, oi flexible thread to the underside of hing pl, the other to the mid-wint oi lill, prevents such movement un less is moved do arcl fro its position parallel to table ri'be extent ol.' rotation of 1nirror it a'lords an index of rate of acceleration,

. plane noch permitting weight classification according to this invention.

Referring to Figs. 1 and l0 particularly, the rate of acceleration of platform 25 and its load is conveniently sensed by the vertical clefleeJ ion oi a beam of light reflect-eel from mirror lli. Using this system, light source IGS, which may be an ordinary 5o c. p. automobile headlight bulb powered by the usual battery source, is `disposed at an angle about from a normal to thc 1nir rors reflective surface. The light reiiecterl from mirror illi is through a collimating lens ist and. impressed on an enclosed phototube 05, which may be of the C. A. 25 type, powered by voltage source llli. The electricalv circuit constituting: voltage source H55, phototube Hit and electrical conductors it? actuates memory deF vice itil, through a built-in electrical relay, to reject articles according to their classiiication as underweight, overweight or acceptable, all in a manner hereinafter more fully `described.

This invention is preferably enfmloyed` in conjunction with automatic reject system, which separates speciiication articles from those not meeting specifications; however, it will be understood that the rate of acceleration detection mechanism hereinabove clesc'ibed may utito merely identify one class of articles so that the articles may be segregated manually in accordance with their classications. Thus, conventional marking devices actuated by the de tecticn apparatus may be used to deposit a mark of distinctive color on non-specification articles, tl entire output then going to a ter-iporary store area Where the separation may be by the plant personnel. Vlhere manufacturing are somewhat lower than .S0-i) units per n'unute, this method is entirely,T practicable.

Referring specifically to operation with autom tic rejection, it Will be understood that the tra el. chains lil is 'co-ordinated, with the operation of platform 26 and its appurtenances by the sprockevchain drive. so that, :hiring the brief ti ne interval that is unlocked, only one arti cle will have its weig it applied to fig. indicated in Fig. 9 particularly, the length of palletwsupporting shoes 3l conveniently be half the length of platform that, in a com plete cycle cl' the locl ing-unloclring mechanism, or for each revolution of drive Wheel 9i, the esuivalent of one pallet will always rest on plat-- f n Titi. During the irst and the last 25% ci each cycle the preceding pallet will process of leavingr 2t while the succo. ding pallet will be entering upon 26 for these portions of the cycle, the weighing platform remains locked. against vertical movement. During the of the cycle the weighing platform is i1 locked, and it is during this interval that the .f ,ight classiiication of each article is effected while the article is being translated at substam tially uniform velocity thereacross..

As hereinbefore described, the entire Weight of the article, the pallet supportingr the article, and the weighing platform and its appurtenances is applied to iloat till immersed in liquid El. The dimensions of float @il are prefere-,bly propern tioned so that, with a single pallet and a representative container lled with the exact weight of product which it is desired to maintain, fioat 58 will descend about 0.005"0.008 in liquid El during the unlocked interval of the weighing cycle. It Will be apparent that precise proportioning of float 60 is not necessary to obtain this degree of platform deflection, since slug pieces of suitable weight may he readily aixed upon the underside of 2t to adjust the rate of descent to the desired amount. in the interests of simplicity of construction it is preferred to locate phototube an appreciable distance (e. g. l or l2 ft.) from millor itil, so that the vertical sweep of the reflected light beam will be correspondingly expanded; however, if space is limited, the same result can be obtained by a multiple mirror reflection system, or in other ways well known to those skilled in the art.

Since under-'weight illling is a condition to be especially safeguarded against in manufacturing, operation of this device to reject under-weight articles will be described in detail, it being understood that the invention is equally applicable to over-weight rejection, or to both under-weight and over-weight rejection by obvious modications.

indicated schematically discarge of which is cci-ordinated l chains As hereinbefore de- "e in sequence is continuously s ighing platform 2t where, during the 'unlocked pI tion of the cycle, its rate of downs/'arc accelelon is sensed by the upward deection of the reflected light from mirror i. Phototube iil is mounted at such a height that only when eac-h article accelerates to the point where the light beam impinges on idc will the reject mechanism ce actuated to non-rejecting position. Under these conditions it will be understood that rmi -weight articles will be rejected, While articles which meet or exceed the prescribed weight vfi`i through as acceptable.

The rejection operation is performed by the overhead reject apparatus indicated generally at H5, Figs. la and 2a, which intersects the line of travel of chains i2 at an acute angle, so that more time is afforded for the removal of nonacceptable articles 2d from pallets 25. As shown, apparatus Il@ preferably comprises an endless traveling chain, only the lower run of which is depicted in the drawings in the interests of simplicity, which is provided with a number of pivcted reject arms lil located at regular intervals therealong so that one will pass across the line of travel of each pallet in turn after the pallets have passed platform 26.

Since rejection is performed at a relatively considerable interval after classiiioation by the deflection of 2t, the operation of reject arms ||1 must be delayed accordingly, so that rejection will not occur until the specific non-acceptable article arrives in the region Where the line of travel of apparatus llt intersects the line of travel of chains i2. lf operation is such that each pallet will always be provided with an article iid, the coordination of operation of ||6 with chains l2 may be effected by incorporating a predetermined time delay in the actuation of i l5. However, it is preferred to forestall spurious rejection due to the occasional absence of an article from a pallet by utilizing a memory apsuoh as 98.

The menno y apparatus |08 shown in Figs. 1 2 comprises a conventional rotating Wheel device provided with a multiplicity of delectible pins of sumcient number such that the one corresponding to a particular article will remain depressed frcm the time of classification to the time of rejection before it is reset by a cam integral iii with the apparatus. This type of device is described in detail in U. S. Patent 2,217,342 and Pratt & Whitney Co. 3-49-413 Circular No. 518 and therefore is not further detailed here. T.t Will be understood that the rotation of the wheel of memory device |68 must be synchronized with the travel of chains I2, and this can be conveniently achieved by driving the wheel with chain ||8 (Figs. 1, 2 and l0) engaging with drive sprocket HQ, keyed to shaft Si, and with driven sprocket i2@ mounted on the rotatable shaft |2| upon which the memory wheel is fixed (refer Fig. l).

In operation as hereinabove described, only articles having a weight in excess of a prescribed minimum will actuate phototube its, whereupon an electrical signal will be impressed through conductors lill on a solenoid or like device incorporated within memory device m3 only when the particular article being classied is acceptable. The corresponding pin of device idd will then be deflected and, as the memory wheel rotates, the signal transmission will be correspondingly delayed until the particular article reaches the rejection region, when the specific pin will actuate cam switch |22 in the reject arm electrical circuit. For simplicity in representation, this electrical circuit comprises conductors |23 and power source |2 (Fig. l) and reject arm-releasing solenoid |25 (Figs. la and 2a). Mechanical design considerations favor a construction of reject arm which is normally spring-biased to rejecting, or lowered, position by individual ccmpression springs IZi by a stationary cam (not shown) in the path of travel of lit. Thus, unless solenoid |25 releases the reject arms to the upper position indicated by ill" in response to a signal that the particular article is acceptable, the particular article is automatically rejected (refer Figs. la and 2a).

Rejected articles, indicated at 24 in Fiss. la and 2a, are deflected from pallets 25 by depending reject arms ll and move laterally on to parallel reject conveyor belt |31, disposed closely adjacent chains |2 and on the same level as the top surfaces of the pallets during upper travel. When all rejected articles are delivered to reject conveyor |3l, a conventional stationary cam (not shown) aotuates all reject arms to the upper, non-engaging position indicated at lil", so that further lateral movement of articles 24 is discontinued, and the rejected articles are carried by |3| to a separate segregation location for salvage or other disposition. Acceptable articles are removed from pallets 25 by stationary deecting arm |32, located in a position clearing the top surfaces of the pallets, and pass over stationary bridge span |33 on to conveyor 34, which carries them to a boxing location or other destination.

If rejection due to over-weight filling solely is the desideratum, it will be apparent that the construction of reject apparatus lit can be mediled so that, in acceptance position, reject arms ||'l will always be pivoted upwards and, at the same time, the location of phototube it with respect to mirror lilo can be altered so that only over-weight articles will actuate arms lil to rejecting, or lower, position. Similarly, if underweight and over-Weight classication are desired simultaneously, a memory device having two rows of pins may be employed together with two phototubes, the over-weight detecting one of which is located above the acceptable weight detecting one. The signals emanating from these asomar two photctubes may be made to actuate reject arms ill' to reject both under and over-weight articles through the agency of means known to the art and therefore not further described herein. When such simultaneous classification is accomplished it will, of course, be understood that the number and arrangement of the reject conveyors may be varied widely to either segregate the rejects according to under or overweight, or to lump both together simply as unacceptable items.

In typical installation processing loaded cylindrlcal at a rate oi" 36u/min., wherein the cans were slid across the weighing platform in direct Contact therewith without the use of interioren diately supporting pallets, the total weight oi the Weighing platform and its appurtenances, including float was lllilil gms. The weight oi a representative can plus a standard weight of fill ing it was desired to maintain was i523 gn so Jhat the total weight applied in a downward direction was flGlB This weight was opposed at balance by an amount of displaced mercury equal to 26l3 gms., making the total weight of the scale system 5226 gms. By actual test, it was determined that addition of 5 gms. weight to platform elevated mirror iilii an amount insufii* cient to actuate phototube Hill to acceptance, while the addition of a total weight of i9 invariably resulted in acceptance. Therefore, the average ci 5 plus i9, or l2 gms., was calculated to be the limiting excess loading deilning the threshold of the acceptance region. 'it is assumed that the difference between l2 and 5, or rl gms.,

constituted the average inaccuracy equivalent :,1.

loading due to frictional and vibrational interferences inherent in the particular device, which probably is a plus or minus quantity at any given instant during operation. The accuracy of olas sincation obtained may be stated on the gross system basis as l9-5 2G 13, equal to approximately 0.5 at, or on the net basis as 19-5/1523, equal to approximately 0.9%. lin operation with this particular device over a relatively long period, check determinations revealed that net accuracy oi' classicaticn of the order of about 1% consistently obtained. Another device provided with pallets for the support of the cans achieved an even higher accuracy by eliminating the eiects ci' can deformation.

From the foregoing it will be understood that the subject invention is capable of the continuous Weight classioation of a succession oi' articles moved along at relatively high speeds and, `lurthermore, that operation is entirely automatic. The limits of classincation accuracy recited are suicient or most industrial. purposes; however, ior special installations requiring higher accuracy it is possible to improve on the design the application of known rennernents in the art so that a considerable increase may be realized. In this connection, it will be understood that, as bolt 5l? is progressively immersed deeper into liquid 6i, a slight inaccuracy is introduced into the classification due to the difference in volume of liquid displaced frorn the at-rest position to the terminally immersed position. The amount of this error may be minimized by reducing the oross-sectional area of bolt within the limits of strength requirements. Another refinement improving the accuracy includes the addition of shock-absorbing pads to all apparatus elements Where vibrations are set up during operation.

'While this invention has been described in detail in connection with the weight classification ci articles in the 3 to l lbs. gross weight, it will be especially understood that the invention is equally applicable to the classioation ci articles much greater or lesser w ight, the apparatus being calibrated for each individual range in each specific instance. Where greater absolute weights are to be handled the physical dimensions of the apparatus elements will necessarily be enlarged whereas, for lower weight applications, these diniensions may be reduced. The type and arrangenent oi "ate oi' aoeel .on sensing apparatus, and rejecting and rei ect removal auxiliary equipment nay oi course, vary widely to suit particular i nents, as will be well understood by persons versed in electro-optical detection and conveying arts.

lftthermore, although this invention has been described with particular reference to a down* wardly aeilecting weighing platform, it is apparent that the relative positions of the pparatus elements may be reversed and the wel g platform calibrated so that weight comparison may be achieved on the up swing equally as well as on. down swing.

By the 'term free translation, employed in the claims, is meant motion in which all the points of the moving artlc'es in process have at any in.- stant substantially the saine velocity and direction or motion, while at the same time the full it ci the lcles is supported by the table or weighing platform directly or indirectly, as 'when pallets are used to eilen-t the movement. It will be apparent that free translation of the artic only necessary over the length of the we hing platform and short distance precedthe platform, tc minimise interfering vibras, whereas the balance of travel may be by lmeans supporting part or all of the weight of the .f 'cle in process.

,-.i'here the weight of the standard mass is against the counterfcrce of the weighing system .in claims, as by the terms balanced counterbalanced "euual or other language, it is substantial euuality of the order constituting about 6.1% tolerance plus or minus. ln practice it is not diilicult to obtain a balance ci? l plus or minus where the standard mass weight is 500i) for a system wherein the deflection of the reilected light beam is about 24 ies.

rom the foregoing, it will be clear that nuinerous :modifications may be ina-de without departing from the spirit o.. 1y invention and I do not intend to limited except as pointed out in the claintis which follow.

c. :or the classiiication el a plu to weight while saisi transiatio' a gasiorm atn4nt velocity comaes substanl'iorlsontally, gravity- 'n having' an article- .fs opposed to a e ocity ci' said i the gravitational oi accelerancn of total mass system u ien arti iividually is disposed on said f x and for deriving a signal a function oi' gravitational rate of llion, ni ans returning said aiticle1eceiv means to original position substantially co vna-r with the path oi horizontal movement of the base portions of said articles after determination of said rate of acceleration, and means segregating said articles in accordance with the individual signals corresponding to each of said articles.

2. An apparatus for the classification of a plurality of articles according to claim l wherein said total mass system comprises an article-receiving weighing platform supported by a float substantially entirely immersed in a liquid having a density suiicient so that the weight of the liquid displaced by said float is equal to the tare weight of said weighing platform plus the weight of said standard mass of known classification.

3. An apparatus for the classification of a plurality of articles according to weight while said articles are in free translation in a gasiform atmosphere at substantially constant velocity comprising traveling chain means moving said articles continuously at a substantially constant velocity horizontally, a smooth table means parallel and contiguous to said chain means contacting the base portions of said articles, a gravity-deflectible total mass system having an article-receiving means with its mass opposed to a standard mass of known classification disposed in prolongation and substantially co-planar with said table, means for determining the gravitational rate of acceleration of said total mass system when each article individually is disposed on said article-receiving means and for deriving a signal which is a function of said gravitational rate of acceleration, means co-ordinated with the travel of each of said articles across lsaid articlereceiving means to cyclically release said articlereceiving means to permit free deflection thereof when each said article is impelled on to said article-receiving means and to cyclically lock said article-receiving means co-planar with said table means while one of said articles is impelled off and a succeeding one of said articles is impelled on to said article-receiving means, and means segregating said articles in accordance with the individual signal corresponding to each said article.

4. An apparatus for the classification of a plurality of articles according to claim 3 wherein said gravity-deflectible total mass system comprises an article-receiving weighing platform retained against longitudinal movement with ref spect to said table means by at least one flexural pivot element having an end fixedly attached to said weighing platform and the opposite end fixedly attached to a stationary support and connecting means on said weighing platform securing said weighing platform to a float substantially entirely immersed in a liquid having a density suicient so that the weight of the liquid displaced by said float is equal to the tare weight of said weighing platform plus the weight of said standard mass of known classification.

5. An apparatus for the classification of a plurality of articles according to weight while said articles are in free translation in a gasiform atmosphere at substantially constant velocity comprising a pair of parallel endless roller chains, powered means driving said roller chains in unison in the same direction at substantially constant velocity, article-impelling cross pins connecting said roller chains together at equal intervals over the lengths, a frame guiding said rollei` chains along an upper horizontal course of travel and a lower return course of travel, a table parallel and contiguous to said upper course of travel of said roller chains contacting the base portions of said articles, said table being provided with an aperture at a point intermediate the ends of said upper course of chain travel for the reception of a weighing platform, a gravity-deflectible total mass system having a weighing platform with its mass opposed to a standard mass of known classification bridging said aperture with sufcient clearance between said table and said weighing platform to permit free vertical defiestion of said weighing platform with respect to said table, means operating in coordination with the travel of each of said articles across said weighing platform to cyclically release said weighing platform to permit free deflection thereof when each said article is impelled on to said weighing platform and to cyclically lock said weighing platform at a level substantially coplanar with the top surface of said table while one of said articles is being impelled off said weighing platform and a succeeding one of said articles is being impelled on to said table, means for determining the gravitational rate of acceleration of said total mass system when each article individually is disposed on said weighing platform during the time interval in which said weighing platform is released and for deriving a signal which is a function of said gravitational rate of acceleration, and means segregating said articles in. accordance with the individual signal corresponding to each said article.

6. An apparatusfor the classification of a plurality of articles according to weight while said articles are in free translation in a gasiform atmosphere at substantially constant velocity comprising a pair of parallel endless roller chains, powered means driving said roller chains in unison in the same direction at substantially constant velocity, cross pins connecting said roller chains together at equal intervals over the lengths, individual substantially identical articlesupporting pallet members attached to each of said cross pins and to succeeding pallets by loose connections permitting application of the full weight of each of said pallets to an underlying supporting surface, a frame guiding said roller chains along an upper horizontal course of travel and a lower return course of travel, a table parallel and contiguous to upper course of travel of said roller chains supporting the full weights of said pallets and the articles carried by said pallets, said table being provided with an aperture at a point intermediate 'the ends of said upper course of chain travel for the reception of a Weighing platform, a gravity-deflectible total mass system having a weighing platform with its mass opposed to a standard mass of known classification plus the mass of one of said pallets bridging said aperture with sufdcient clearance between said table and sai-"l weighing platform to permit free vertical deflection of said weighing platform with respect to table, means operating in co-ordination with the travel of each of said pallets across said weighing platform to cyclically release said weighing platform to permit free deflection thereof when each said pallet is impelled on to said weighing platform and to cyclically lo .i said weighing platform at a level substantially co-planar with the top surface of said table while one of said pallets is being impelled off said weighing platform and a succeeding one of said pallets is being impelled on to said table, means for determining the gravitational rate of acceleration of said total mass system when each said article-supporting pallet member individually is disposed on said weighing ne interval Vin which said on, andA means l Vice with the individual -g to ch arti'le.

or the classification of a plu.- ff to claim 6 wherein u n a liquid having a denthe weight of the liquid al to tire combination ts the weight of ition, conM peil@ weLhing .p c id lateral retaining zform including a plurality e1 's fixedly attached to nii. a stationary supation ci a pluo' wherein fit t nal i. me interi?C wl r released and for ra ion compi the un on.

apparatus Aor the classication rality or articles according to claim 6 wherein said means for determi g the gravitational of acceleration of the total mass system during the e inte val in which said weighing platform r and for indicating' said rate of acceleration comprises a light-reilecting mir ror deiie-ctible tlirougl'i a distance proportional to the deflection of said weighing platform, a stationary light directing light at said mirror, and at least one light-sensitive element responsive refi eeter-l light from said mirror disat po ion corresponding to the nite 'rei-light displacement llor a mass within a ying known classification, and means including memory device responsive to said `light-'sensitive element actuating said means segregating articles accordance with the individual signal corresponding to each said article.

lr An apparatus for the classification of a plurality of articles according to weight while said articles are `free translation in a gasiform atmosphere at substantially constant lvelocity comn a pair of parallel endless roller chains, powered means driving said roller chains in unison in the same direction at substantially constant elocity, cross pins connecting said roller chains together at equal intervals over the lengths, individual substantially identical articlesupporting :niiet members attached to each of said cross pins and to succeeding pallets Yby loose `connections permitting application of the full l 5 Weight of each of said pallets to an underlying supporting surface, a frame guiding said roller chains along an upper horizontal course of travel and a lower vreturn course of travel, a table parallel and contiguous to said upper course of travel of said lroller chains supporting the full weights 0f said pallets and the articles carried by said pallets, said table being provided with an aperture at a point intermediate the ends or said uw per course of chain travel for the reception of a weighing platform, said weighing platform oomprising a plane-surfaced plate, vertical supporting means including a float substantially entirely immersed in a liquid having a density sufcient so that the weight of the `liquid displaced said float is equal lto the combina on or the tare Weight of lsaid Weighing platform, the weight of any elements depending therefrom, the weight of one of said pallets and the weight of said standard `mass of known classification, connecting means depending from said weighing platform for attachment of `said weighing platform to iioat, vand lateral retaining for said weighing platform including a plurality ci flexural pivot elements xedly attached to said weighing platform and to a stationary support, means operating in co-ordination with the travel of each `of said pallets across said weighing platform to cycli- `cally release said weighing platform to permit free deflection thereof when each said pallet is irnpelled on to said weighing platform and to cyclically lool: weighing plattform at a level substantially cwplanar with the tcp surface of said table while one of `said pallets is being impelled off said weighing table and a succeeding one or said pallets is being impelled on to said table, a light-reflecting mirror journaled on a stationary support, connecting means between said weighing platform said liglit1eiiecting mirror causing proportional ole-riection of said mirror when said Weighing platin-rn is deiiected, a stationary light source o light at said mirror, at least one phototube responsive to relected light from vsaid mirror disposed at a position corresponding to the iinite mirror-iight isplacement for a within a limiting known classification, means including a mei .tory device responsive to said photo-tube, and responsive to said memory device for segregating said articles in accordance with the light displacement corresponding to each article comprising at least one article-displacing ine-ans disposed superjacent said roller chains, said last-mentioned means being provided with article-displacing elements actuated to article-displacing position by an appropriate signal emanating from said memory ldevice and an article-reeel ing conveyor cri-operating with each of said article-displacing means for the reception of articles displaced by said last-mentioned means.

NORVHJ G. IIIALDNEY.

in this 'UNIlED STATES PATENTS 

